I am going to write a more proper piece on an investment strategy I stumbled across called value cost averaging in which you basically make your monthly allotments such that all positions are boosted by same percentage amount. So those that grow fastest, you put the least of and those growing slowest you buy the most of. Simple math guarantees you’re buying shares at lower prices (ie not at their ATH).
To pick up other coins outside top five just allocate 80% to top five and 20% to discretionary picks like NEO, OMG, QTUM, etc. or. 100% into top N and then monthly, buy any of the others.
There’s always pros and cons so decide on overall strategy and then execute. Plus, don’t be afraid to pivot as you become more educated and fine tune your thinking.